santon premier problems

[James1987]

hi I am an heating enginer and I am having problems wit an unvented cylinder. when I turn only hot water on on the programmer after 40 mins I get hot water coming out from the f&e tank in the loft from the 22mm feed pipe causing it to over flow out side any idea what it could be I have tried thermostats and diverted valves what am I missing help help help

 

[diamondgas]

Are you saying here that your heating system is an open system yeh? When you turn it off does the water level go down?

 

[James1987]

well there is a f&e tank in the loft but no open vent and yea water level drops again when its off

 

[diamondgas]

Sounds like a combined feed and vent is fitted and most likely on the positive side of the pump if it's only filling when the pump is turned on ..... Check that all the radiators are full, no air in them,the air pockets can expand if the radiators are on the negative side of the pump forcing the displaced water only one way, up to the f&e! Check the water level cold on the f&e ... only need it to cover the feed connection about 1/3 full!

Hope this helps

 

[James1987]

would that apply cause it only happens when the hot water is on but dosent do it when heating and hot water are on if you see what I mean thanks for all this info its very helpful

 

[diamondgas]

May be there isn't such a pressure diff around the combined f&v when the whole circuit is open ? It's worth investigating the possibility James

 

[James1987]

thank you I will try looking at the radiators and the feed tank

 

[diamondgas]

thank you I will try looking at the radiators and the feed tank

I can't think of anything else that'll raise the level of the water to such a degree and it be hot too Let us know how you get on.... maybe someone here has other thoughts to put your way

 

[darren bastin]

How big is the system? Are you getting any overheat situations? Is it worth converting it to a sealed system, if the boiler is compatable.

 

[James1987]

when it dose pour out the boiler over heat stat pops out its quite a big system but not comparable for sealed would I just need to seal it put a filling loop and a pressure gauge and an expansion vessel

 

[diamondgas]

when it dose pour out the boiler over heat stat pops out its quite a big system but not comparable for sealed would I just need to seal it put a filling loop and a pressure gauge and an expansion vessel

Now that puts a different slant on the issue .... Boiler overheating will give rapid expansion within the system, the f&e being the only place to expand into .... What make and model boiler we talking about here? You'll need to check the mi's to see if it can be installed on a sealed system. ... .

 

[James1987]

I will find out und get back to you